We have never used the low power listen mode since this does not match our use-case for the LPS: the Crazyflie needs fast ranging when flying and the motors consumes a big percentage of the total power anyway. The lowest power I have done is by tracking TDMA in the TDoA anchor: a single TDoA anchor does not consume enough to keep some USB battery pack powered, this is because the listen mode is only enabled when a packet is expected.